Lifeline AGM Opinions

[Holding Pattern]

I always like to poke brains...

Looking for opinions on Lifeline AGM batteries. Looking into them for our 40' cruising ketch, we liveaboard fulltime, have 3 75w solar array + four winds mizzen mount wind gen.

I have done my research and know the good and bad but I want to know what everyone else thinks.

Brian

[Vasco]

Brian,

There is increasing opinion that AGM's aren't what they're cracked up to be when it comes to cruising. It seems that the way cruisers use them (seldom fully charged, usually charging up to 80 - 85%) is not conducive to long life for AGM's. This is all anecdotal but more and more this is what I'm hearing. I was going to go the AGM route but have decided to stick with floodeds. I only wish I could fit those 6 volt jobs from Sam's Club in but they're a bit too tall for my space.

[ssullivan]

I hear the same things Rick does about them. I went for Trojan T-105 6v golf cart batteries. I haven't seen a power cord from a dock since March or so. Even cycling them every single day, I have seen no dip in performance at all to this date.

I drain them out to about 60% full charge each day or so, then fill them back up with a 1hr genset run. No troubles at all. Very good batteries. I went to add water yesterday, and they were completely full. Having a good charge helps with battery life though, I think.

[ssullivan]

I hear the same things Rick does about them. I went for Trojan T-105 6v golf cart batteries. I haven't seen a power cord from a dock since March or so. Even cycling them every single day, I have seen no dip in performance at all to this date.

I drain them out to about 60% full charge each day or so, then fill them back up with a 1hr genset run. No troubles at all. Very good batteries. I went to add water yesterday, and they were completely full. Having a good charge helps with battery life though, I think.

[Pblais]

I'll be contray and say by 2 group 4 lifeline's are performing quite well. Add a battery monitor and yoyu should be fine. You do need to tweak the charging system a bit. AGM's are way better than Gels.

The bonus of AGM's is less amps in yields more amps charged.

[Nepenthe]

Brian,

Regular Trojans have worked for me just fine.

Question: How do you like the mizzen mounted wind generator. I'm about to do the same and I'd like to hear your opinion.

Thanks,

John

[Sandero]

I use 8D AGMs and see no difference between their performance and other types if maintained. But it is hard to compare performance unless it under controlled contidition. Since we are weekend sailors these days, the solar cells keep everything tiopped up. Our frig is engine drive and so we do run the engine at min a couple of hours each weekend for the frig and hot water. So far so good. I like the no maintenance aspect... and no gasing. I do have all the dodads such as Sulfator, Echo charge, solar regulator, link monitor and 3 stage Balmar charger with 120 amp alt.

Jef
sv Shiva
Contest 36s

[ssullivan]

I think that unless you are cycling the batteries deeply all the time, battery life will have more to do with how well you keep them charged up and full of electrolyte. Jef's right.

[Vasco]

Again, the knock on AGM's is that they don't last if you're cruising. If you live in a marina or use the boat on weekends, that's a different story. As you know, getting the last 15% into the batteries is the hard part of charging. When cruising it's just not worth it most of the time. Again this is anecdotal but I have seen some explanation as to why this is with AGM's but unfortunately I can't find it. The thing I do remember is that AGM's work best when fully charged all of the time.This is great for power boats or boats with generators but not the best for your average cruiser.

[Pblais]

All batteries perform best when fully charged so type is not an issue. The charging of the last 15% is a problem with all batteries since the acceptance charge is low and it takes a long time. The plus with an AGM is they have lower internal resistence and so require less power to be put in to charge them. Gel batteries have more problems than either flood or AGM. With Gel batteries I can see no advantages. They don't need water added is about the end of the list. AGM's cost more and so there is a lot disinformation about them so that some people can think the cheaper batteries are always better.

All batteries should never be discharged more than 50% if you want them to last a long time and it is best when recharged that they be fully recharged. No difference in what type you use. I've used both Trojan and Lifeline batteries. Lifelines can be mounted upside down or sideways and be put in hard to reach places then forget about them. They install any place you can fit them. You just make sure they don't flop around.

You can not do that with flood batteries - they have to be level and flood batteries require good venting. I'ld use battery boxes in case they leak. The SO2 from 4 Trojans was eating my A/C compressor from the battery outgassing. These installation issues are what caused me to switch on my old boat from Trojans to Lifelines. The Trojans were all dead but they lasted about 7 years. My new boat has Trojans. I'll keep them.

Good battery regualtion is important and you may need to adjust your regulator (and your shore charger) in order to switch battery types. Checking them would always be a good idea. The smart regualtors have specific settings for both types and they matter if you want to get the most out of them.

[hellosailor]

Rick, I'd be curious if you can find any specifics on why AGMs shouldn't be as good as wet lead for cruisers.

Offhand, if you are using wet lead ... in order to properly recharge them I guess you have to be motoring (not sailing) because heeling over even ten degrees would mean the plates would be partly above the electrolyte and wet cells literally couldn't be recharged properly in that position, could they? Sailing and using wind or solar charging would be problematic, unless you made sure to level the boat, or you had batteries with enough electrolyte to make sure it could work at that angle.
No?

Brian, when all else is said and done, AGM will cost you about 30% more than wet lead, and that's a real factor. Less so after you've replaced a few acid-burned clothes.<G>

[Vasco]

hellosailor,

more discussion on problems with AGM's.
http://www.sailnet.com/forums/island...batteries.html

[hellosailor]

Rick-
Thanks, I'm aware of that thread. All it boils down to, is that one user has had one problem of capacity loss--from causes unknown. And, that his problem might or might not be because he needs to equalize the batteries, which LifeLine recommds--but other AGM makers expressly forbid. (Especially at the voltages LifeLine use.)

Doesn't really say anything about AGMs from any other maker, or about any AGM problems in general. It only speaks to one apparently very different brand of AGM, and one problem still unresolved.

[Vasco]

hellosailor,

Like I said the evidence is anecdotal. There are quite a few stories like this including one that Ample Power (one of the first outfits to cater to cruisers' electrical needs) does not recommend AGM's. It appears that if you do not charge them right up each time they lose their capacity faster than flooded batteries.

[coot]

Originally Posted by hellosailor

And, that his problem might or might not be because he needs to equalize the batteries, which LifeLine recommds--but other AGM makers expressly forbid. (Especially at the voltages LifeLine use.)

Actually, what it says on the sheet that comes with the battery is:

Equalizing should only be done when the battery is showing symptoms of capacity loss.

I have 4 of the Lifeline 8D batteries. The ability to mount the battery at odd angles was instrumental in my choosing AGM -- two of the batteries are stored on the small end. (That is, turned so they take up about 10x10 inches of floor space, but are almost 30 inches high.) Without this feature, I would only have room for two batteries, and so half the capacity.

The charge rate was another feature. You can push energy into an AGM faster, though I don't recall exactly how much. The result is a shorter charge cycle. I have observed my 840 AH of AGM batteries accepting 160 A of charge current at the beginning of the cycle. (The limiting factor was the 150 A battery charger, and yes 160 > 150 but only by 7%.) Of course, this drops off quickly as the batteries are charged, but 160 A for 5 minutes is worth 30 A for 25 minutes, so it really does help.

The "last 15%" is a problem with any battery, but with my usual at-anchor charge regimen, it is only the "last 5%". That is, I charge up to about 800 AH from the generator. I've always planned to get solar panels to provide the last 40 AH/day, but it hasn't been a priority.

One of the reasons I wanted 840 AH instead of 420 AH (with 2 of 8D AGM) or 240 AH (with 2 flooded batteries installed by Beneteau) is that I can routinely discharge my batteries only to about 80% and then recharge to 95%. My peak power budget is sailing at night in cold weather (lights/instruments/heaters running), but even that stays above 50% discharge.

I'm happy with these batteries (and the associated electrical system), but partly that is because my system is designed to make effective use of them. For example, if you get 800 AH of batteries and try to recharge them with a 30 A battery charger, you won't see the benefit of the higher charge rate.

I have not noticed any degradation over 2 years, but beyond the description above, I'm also pretty nice to them by spending a lot of time on shore power. e.g. I was at the dock most of this summer, waiting for cooler weather to go sailing. I'm happy with these batteries, but you can always ask me again in a few years.